For example, eye images have been shown to increase human charitable donations in shopping malls 36 and to decrease bike theft 37. Conceivably, eyespots may have multiple anti-predator mechanisms, depending on the attacker, which are not necessarily mutually exclusive.Īlthough no known contemporary mammals display anti-predator eyespots, the effects of eye patterns and gaze have been shown to modify behaviour in this Class including in humans 36, 37, 38, domestic and wild canids 39, 40, 41, and domestic cats 42. In this case, eyespots may mimic prey vigilance, discouraging attack 34, 35. These ‘pursuit-deterrent’ signals cause predators to re-evaluate the hunt based on the costs associated with the signal. A further possibility, which has been suggested for some raptors 32, 33, is that eyespots may deceive predators or ‘mobbers’ into perceiving they have been detected, thereby preventing an attack (the “detection hypothesis”). Other studies have highlighted the importance of conspicuous eye-like signals occurring in pairs to be effective as anti-predator signals 29, 30, 31. Some research suggests that eyespots simply act as deflection targets to divert attacks to non-vital body regions (the “deflection hypothesis”) 2, 12, 13, 14, 15, 16, 17, 18, while others suggest that eyespots are intimidating, either by mimicking the eyes of the natural predators of would-be attackers (the “predator-mimic hypothesis”) 2, 8, 19, 20, 21, 22, 23, or alternatively by representing a novel or rarely encountered conspicuous feature that could promote avoidance behaviour (the “conspicuousness hypothesis”) 24, 25, 26, 27, 28, 29. While these patterns ostensibly resemble a vertebrate eye, the mechanism behind their anti-predator effects remains debated 7, 8, 9, 10, 11. A classic example of anti-predator markings are eyespots on moth and butterfly wings 2, 3, 4, 5, but many other animal groups including other insects, fishes, molluscs, amphibians and birds, use concentric circles to deter predators 1, 2, 6, 7, 8. Visual signals may reduce predation risk through camouflage, warning colouration, divergence and mimicry 1. Applying artificial marks to high-value livestock may therefore represent a cost-effective tool to reduce livestock predation.Īnimals have evolved numerous strategies to avoid being eaten. To our knowledge, this is the first time eyespots have been shown to deter large mammalian predators. While higher survival of eyespot-painted cattle supports the detection hypothesis, increased survival of cross-marked cattle suggests an effect of novel and conspicuous marks more generally. Cattle painted with eyespots were significantly more likely to survive than were cross-marked and unmarked cattle, despite all treatment groups being similarly exposed to predation risk. Here we show that eyespots painted on cattle rumps were associated with reduced attacks by ambush carnivores (lions and leopards). Although eye patterns and gaze modify human behaviour, anti-predator eyespots do not occur naturally in contemporary mammals. There remains debate regarding whether eyespots function as diversion targets, predator mimics, conspicuous startling signals, deceptive detection, or a combination. Eyespots evolved independently in many taxa as anti-predator signals.
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